On the Impact of Mass Screening for SARS-CoV-2 through Self-Testing in Greece

The emergence of COVID-19 stressed country health systems up to the point of triggering compulsory public health interventions to flatten the epidemic curve. Most of the interventions during the first year of the pandemic were non-pharmaceutical and aimed to reduce the contact rate of the people, which reduced the transmission rate of all respiratory pathogens, but had a large social and financial burden. SARS-CoV-2 specific interventions included screening, that is testing of asymptomatic people, which was largely facilitated by the availability of self-testing lateral flow antigen detection devices. The importance of self-testing interventions in controlling COVID-19 epidemic is not well-documented. We study as a paradigm-model the self-testing COVID-19 mass screening program that was implemented in Greece, involving large, susceptible populations taking tests routinely and pre-emptively so as to enable early detection of infections. Using a novel compartmental model we quantify the effectiveness of the program in curbing the COVID-19 pandemic. Conservative estimates indicate that the program reduced the reproductive number by 4%, hospital admissions by 25% and deaths by 20%, which translated into approximately 20,000 averted hospitalizations and 2,000 averted deaths between April-December 2021. Self-testing mass screening programs are efficient interventions with minimal social and financial burden, thus they are invaluable tools to be considered in pandemic preparedness.